This disclosure relates generally to roofing systems for low slope roofs (including flat roofs) and, in an example described below, more particularly provides a device for distributing granules on a low slope roof for protecting portions of the roof from various environmental conditions.
There are several types of roofing systems used to cover a low slope roof. An underlayment is generally constructed of multiple layers that provide strength, insulation, and some degree of weatherproofing for the roof. The exterior layer is exposed to the most damaging environmental conditions, such as the sun's UV rays, rain, temperature extremes, hail, ice, wind, etc. Therefore, this layer provides the first line of defense against these conditions and generally determines the useful life of the roofing system.
One roofing system for covering low slope roofs uses poured asphalt with pea gravel covering the poured asphalt. The asphalt is heated until it can be poured onto the roof and then cooled after it is smoothed out to provide waterproofing for the roof system. Pea gravel may then be distributed over the asphalt to provide protection for the asphalt from environmental conditions.
A modified bitumen system was developed in Europe during the sixties and introduced in the U.S. in the early seventies. The term modified refers to the addition of plastic or rubber-based polymeric binders to asphalt for improving its performance and durability. Modified bitumen is a multiple layer system and is essentially a “factory assembled” build-up roof. Several coats or laminations of modified bitumen may be used as a reinforcing mat, which is often covered with a granule-surface cap sheet, or left smooth for aluminum or white coating to be applied.
These granule-surface cap sheets may be individually installed on the roof by applying an adhesive to the roof and rolling out the individual sheet over the adhesive. Alternatively, the cap sheets may be installed by heating a bonding material (e.g. asphalt, an adhesive, etc.) on a backside of the sheet until it is soft and rolling the cap sheets with the heated bonding material onto the roof. The heated bonding material will then adhere to the roof and secure the sheet to the roof.
Installation of subsequent sheets of the roofing material may be performed by 1) overlapping a portion of the new sheet over an adjacent previously installed sheet, 2) applying an adhesive to the roof and/or heating the bonding material of the sheet, and 3) rolling out the individual sheet onto the roof while maintaining the relative overlap between the two adjacent sheets. The edge of the top sheet in the overlapped region may be referred to as a seam of the roofing system 10 (see FIG. 1).
The seam may also include bonding material that may ooze from the overlapped region onto the roof. The bonding material may not be suited to withstand the harmful environmental conditions without additional preparation.
Therefore, these roofing systems generally cover the seams with the same type of granules used on the granule-surfaced cap sheets. This serves to match the color and texture of the rest of the roof, to prevent operators from tracking the oozed adhesive around the roof, and to protect the oozed adhesives and/or asphalt on the seams from the harsh environmental conditions, thereby extending the useful life of the roofing system.
Unfortunately, the usual method for distributing these granules is for laborers to carry the granules in a bucket (or suitable container) onto the roof and scatter the granules by hand along the seams to cover the seams with the granules. This approach is very labor intensive and may result in inefficient and inconsistent distribution of the granules. Therefore, it may be seen that improvements in the art are needed.